Eighty five percent of the world’s energy supply comes from burning fossil fuels, and this will most likely be the case for a few decades, according to assistant professor Yiguang Ju. In Princeton’s mechanical and aerospace engineering department, Ju and Professors Frederick Dryer and Chung K. Law are making the best of that reality by studying the combustion of conventional and alternative fuels to harness their energy with maximum efficiency.

Their understanding could lead to the best possible burning methods, improved engines and the safe use of hydrogen as a fuel.

These researchers, for example, are studying the burning and emission properties of dimethyl ether and syngas, synthetic fuels that can be derived from coal or biomass. Syngas could drive power plant turbines, generating less particulate pollution and mercury than coal. “If you make syngas from biomass and then sequester the CO2, you could negate overall CO2 emissions,” Ju said. But controlling the ignition and combustion of syngas can be difficult, a problem that Ju is tackling in research funded by the U.S. Department of Energy and the American Chemical Society.

Dimethyl ether, a diesel and cooking fuel substitute, emits low amounts of nitrogen oxide and no soot, he said. In another project, he is collaborating with researchers at China’s Tsinghua University to examine the impact on nitrogen oxide emissions when ethanol is added to gasoline. Ju’s work could slash the emissions from dimethyl ether and ethanol, benefiting their use in China and other developing countries.